Hayek: A Collaborative Biography: Part XV: The Chicago School of Economics, Hayek's 'luck' and the 1974 Nobel Prize for Economic Science by Robert Leeson
The evidence suggests that Hayek's fraudulent assertion was uncovered at the University of Chicago in the early 1930s - but not reported. The most likely explanation is self-censorship - for reasons of ideological correctness, fund raising and residual deference to the Second Estate. Four indirect tests suggest that 'free' market economists have - in other instances and presumably for fund-raising motives - suppressed embarrassing 'knowledge': which suggests that they were perfectly capable of suppressing 'knowledge' about Hayek's non-prediction of the Great Depression.
With respect to the Nobel Prize and thus his ability to reach a wider audience, Hayek was fortune in having two loyal 'intermediaries': Lionel Robbins and Fritz Machlup who were - and probably felt themselves to be - 'socially' inferior to 'von' Hayek.